Automatic block-signaling system for electric railways.



O. E. STEVENS. AUTOMATIC BLOCK SIGNALING SYSTEM FOR ELECTRIC RAILWAYS.

APPLICATION FILED NOV. 3, 1908.

Patented-Apr. 21, 1914.

UNITED STATES PATENT OFFICE.

OSCAR EGERTON STEVENS, OF NEW YORK, N. Y., ASSIGNOR TO GENERAL RAILWAY SIGNAL COMPANY, A CORPORATION OF NEW YORK.

AUTOMATIC BLOCK-SIGNALING SYSTEM FOR ELECTRIC RAILWAYS.

Specification of Letters Patent.

Patented Apr. 21, 1914.

Application filed November 3, 1908. Serial No. 460,904.

To all whom it may concern:

Be it known that I, OSCAR Eonnron STEVENS, a citizen of the United States, residing at New York city, county and State of New York, have invented certain new and useful Improvements in Automatic Block- Signaling Systems for Electric Railways, of which the following is a specification.

My invention relates to that type of an tomatic block signaling systems wherein the track rails separately serve as return paths for the power current to the power generator are divided into block sections, and the signaling devices therein are automatically controlled by the movement of the motor vehicles into and out of the block sections.

Heretofore it has been the practice to energize the signal controlling device employed, by a difference of signaling current potential impressed upon the block section in which the controlling device was located. My invention differs therefrom in that, first: the signal controlling devices of the system are normally deenergized. Second: the signal controlling devices of the system are nor mally controlled by the signaling current impressed upon adjacent block sections. Third: the signal controlling devices may be individually arranged to control a plurality of signals. There are also other features of diiference, which will be apparent to those skilled in the art, from the specification and claims.

The objects of my invention are to generally improve automatic systems of block signaling by increasing the safety factor and by decreasing the cost of installation and operation, the first condition being obtained by the fact that positive movement is imparted to the signal controlling device in opposite directions, instead of depending upon the action of a weight, or spring for movement in one direction as is usual, and the latter condition by providing that the signal controlling device may be normally deenergized, thereby decreasing the cost of.

the signaling power apparatus and provid ing that the signaling current consumed shall be in accordance with the trafiic.

My improved system is applicable for use on electric railways or steam railways.

The accompanying diagram will serve to illustrate my invention. In this diagram the trackway is shown continuous and the signal controlling devices are arranged in inductive relation with the track rails.

I wish it understood that the diagram is merely an illustration of an arrangement which may be made embodying my invention and that in practice very many other arrangements may be made having in mind the employment of devices such as bonds, inductive and otherwise, phase controlling devices, relays, cross-connections between parallel track rails, special control of sig nals by means of a plurality of relays, etc., such as are now well known to signaling engineers.

Referring now to the figure: r is a source of power current fed to the motor vehicle to by the conductor 1, and returning thence to the source of power P by the rails 2, 3. This power current may be either direct or alternating.

S is a source of alternating signaling current and is fed to the block signaling conduotors 4, 5. The rails 2, 3 are divided into blocksections U, V, lV, X, Y, by the circuit closing crossbonds 13 as in patent to Young and Townsend No. 77 1,5313.

7 is a coil laid in inductive relation to the rails 2, 3 substantially as shown. This coil 7 has one part, 9 in inductive relation to the closed track circuit of one block and another part, 10 in inductive relation to that of an adjacent block. It will be seen that inasmuch as the power current flows in the same directions in rails 2, 3, the power our rent will have no inductive efiect on the coils 7% Transformers 14, 14, 1 1 have their primaries connected. across the signaling line wires 4:, 5, and their secondaries are connected across the rails of the block. In the diagram these transformers are shown connected substantially to the center of the block, but I do not wish to be limited to this particular arrangement, for, in actual practice, conditions will arise which may make it advantageous to connect these transform-v type with windings 15 connected to coils 7. Other windings 16 are connected across the source of signaling current S, either directly, as shown in the diagram, or through the instrumentality of a transformer. This relay 12 has a rotor member 17 on which is an arm 18 which, when the relay is energized in a certain way, makes contact with contact 19 and thus closes the local circuit 20 and operates the signal mechanism 21.

The operation of my system may be briefly described as follows: Normally, that is when no train is present, the relay devices 12 are denergized for the reason that current flowing in the closed track circuit of one block opposes that of the adjacent blocks on parts 9 and 10 of coil 7*, and there is, therefore, no electromotive force induced in winding 15 to operate the relay device 12. When a train, such as w, enters a block, such as lV, it shunts the transformer 14 of that block W and allows the transformer let of the preceding block X to act inductively 011 that part of coil 7 that is in inductive relation to the rails of block X. This excites an electro-motive force across the terminals of coil 15 of relay device 12. The relay device 12 is then energized to close a local circuit 20 and so actuate the signal to the proceed position. If, however, there is a train in the preceding block X, the relay 12 will not be energized for the reason that the transformers of blocks and X are both shunted through the two trains and there is no E. M. F. induced in winding 15 of the relay device 12. hen a train to passes into a block, such as X, it shunts the energy from part 9 of coil 7 This allows part 10 of coil 7*, to be influenced by transformer 14 of block IV and to induce an E. M. F. in the relay member 15 to operate this relay, but inasmuch as this E. M. F. will be opposite in polarity from that induced in'coil 15 when part 9 actuates the relay it will open the relay and cause the signal to go to the danger or stop position behind the train.

It will be noted in the above described embodiment of my invention that all the signal instrumentalities, including the track circuits, do not normally absorb electrical energy, and that the energy for operating the signals is only expended when trains are present and in direct proportion to the number of trains that would be present upon a given'line of railroad. This would obviously vgreatly decrease the cost of installation of signaling apparatus and the operation of a system. My invention also increases the safety of operation by being a normal danger signaling system and one that is normal danger from the track circuits. It also increases the safety of operation, due to the fact that the relay device is actuated by electrical energy to the open or danger position after the passage of a train into a block. It is thus seen that where formerly a relay device has been actuated to the danger or open position, by gravity or the tension of a spring, it is in my invention actuated to this position by electrical energy instead of, or in addition to, gravity or the tension of a spring. This fact does away with any possibility of the relay device sticking closed after the passage of a train into the preceding block, also should a broken rail or broken bond wire occur, the danger of a false signal is removed. Moreover it would be obvious to electrical engineers that since I have disclosed a relay which is actuated by electrical energy in two directions, a plurality of signals may be controlled by said relay, such as home and distant signals or two home signals, one governing traffic in one direction and the other governing trailie in the other direction, and other variations of signal control and arrangement that are well known in the art.

The transformers letshould be, preferably, of poor regulation, so that when a train on is in block the E. M. F. set up across the rails will drop to such a low value that there will be substantially no excitation of winding 15 by part 9 of coil 7.

I do not wish to limit myself to any types of relays, translating or transforming devices, for any relay, translating or transforming device, known in the art, could be adapted to operate in my invention, nor do I wish to limit myself to any particular type of track circuit or reaetance bonding between parallel rails or between adjacent block sections. I have only endeavored to show in these figures a few of the uses or embodiments of my invention. Nor do I wish to limit myself to signaling current of only one frequency or phase for it is well known that. additional protection against false operation may be obtained by multiplying the number of signaling frequencies and phases.

Having thus described my invention I claim 1. In a signaling system for electric railways, the combination of a source of pro pulsion current, a feeder, a trackway the rails of which are continuous and form return paths to the source of propulsion current, a source of signaling energy, a transformer in each block section fed from said source of signaling energy and having its secondary connected across the trackway, conductive bonds connecting the rails at the limits of a block section, a coil located in two adjacent block sections and in inductive relation with the rails, and a relay having one member fed from the source of signaling energy and the other member from said coil.

2. In a signaling system for electric railways, the combination of a source of propulsion current, a feeder, a trackway both of the rails of which are continuous and are connected to the source of propulsion energy, a series of conductive bonds dividing the trackway into block sections, a series of coils in inductive relation with the rails and located so that one-half of each coil is in one block section and the other half of the coil in an adjacent block section, a source of signaling energy, means for inducing a difference of potential across the trackway fed from said source of signaling energy, and a series of relays each having their coils energized from across the source of signaling energy and from a coil in inductive relation with the trackway.

3. In a signaling system for electric railways, the combination of a source of propulsion current, a feeder, a trackway the rails of which are electrically continuous and serve as return paths to the propulsion generator, a series of non-inductive crossbonds dividing the rails into block sections, a coil at the end of each block section, said coil in inductive relation with the rails of two adjacent block sections, a source of signaling energy, means for exciting a signaling diii'erence of potential located approximately midway in the block sections, and polyphase relays each energized from the source of signaling energy and from a coil in inductive relation with the rails.

4. In a signaling system for electric railways, the combination of a source of propulsion current, a feeder, a trackway of which the rails are electrically continuous and connected to the source of propulsion current, bonds dividing the rails into block sections, a source of signaling current, means energized from the source of signaling current for exciting a difference of potential across the block sections, a coil situated at each bond in inductive relation with the rails of adjacent block sections and relays having one member energized from the source of signaling energy and the other member from the coil in inductive relation with the rails of the section in which the signal is located.

5. In a signaling system for electric railways, a source of propulsion current, a feeder, a trackway of which the rails are continuous and connected back to the source of propulsion current, means for dividing the rails into block sections, a source of signaling current, means for exciting a difference of signaling potential across the rails, a normally denergized relay, a motor vehicle, means for actuating the relay in advance of the motor vehicle to indicate the condition of the section in advance, said means consisting of a coil normally in in ductive relation with the rails of two ad jacent block sections, and a relay having one member energized from the source of signaling energy and the other member from said coil.

6. In a signaling system for electric railways, a source of propulsion current, a feeder, a trackway of which the rails are continuous and connected back to the source of propulsion current, means for dividing the rails into block sections, a source of signaling current, means for exciting a difference of signaling potential across the rails, a normally deenergized relay, a motor vehicle, means for actuating the relay in advance of the motor vehicle to indicate the condition of the section in advance, said means consisting of a coil normally inductively aifected by current in the rails of two adjacent blocks but abnormally affected by current in the rails of the block section in advance of the motor vehicle, and a relay having one member energized from the source of signaling energy and the other member from said coil.

7 In a signaling system and in combination with the rails, means for dividing the rails into block sections, means for exciting a difference of signaling current potential across the block sections, a coil in inductive relation to the rails of adjacent block sections, opposing diiferences of potential induced therein by the current flowing in the rails of the adjacent block sections, and a relay having one member connected to said coil, said member adapted to be energized when one of said opposing differences of potential in said coil is destroyed.

8. In a signaling system, a signal, a track way, means for dividing the trackway into sections, means for impressing a signaling current upon each section, a device adapted to be inductively affected by the flow of signaling current in adjacent sections and a relay governed by said device for controlling the signal.

9. In a signaling system; a signal; a trackway; means for dividing the trackway into sections; means for impressing a signaling current upon each section; a relay for controlling the signal; means governed by the joint action of the signaling currents in adjacent sections for governing the relay.

10. In a signaling system for electric railways,the combination of a source of propulsion current, a feeder, a trackway the rails of which are continuous and form return paths to the source of propulsion current, a lation with the rails, and :1 relay connected source of signaling energy, a transformer in thereto. 10 each block section fed from said source of In testimony whereof, I afiix my signasignaling energy and having its secondary ture, in the presence of two witnesses. connected across the trackway, conductive OSCAR EGERTON STEVENS. bonds connecting the rails at the limits of Vitnesses:

a block section, a coil located in two ad- PHILIP A. JACKMAN,

jacent block sections and in inductive re- MINNIE E. KoELsoH.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. C. 

